: Many attempts have been made toward the development of HIV-1 vaccine with little success. Clearly such efforts must be continued. Ideally, HIV-I vaccine should be completely safe without any complication of replicating viruses but with the capability of inducing protective immunity against the whole range of HIV-I strains. The goal of this project is to exploit the use of baculovirus multigene expression technology, a major new technological development, for generation of noninfectious HIV virus-like particles (VLPs) to develop safe and effective HIV vaccines. Various modifications will be made to improve the productivity and quality of VLPs including the level of gp160 incorporation into the Gag VLPs as well as an antigenicity gp160. A signal sequence of gp160 will be replaced by that of gp64, baculovirus glycoprotein, to improve the efficiency of cleavage of signal sequence that could enhance proper protein processing. The effect of co-expression of molecular chaperons, calnexin, on protein folding and processing also will be investigated. To generate the mature form of gp120/gp41 from the precursor gp160, a cleavage protease, furin, will be provided in trans in insect cells which lack this enzyme. The immunogenicity of those modified VLPs produced in different insect cell lines which differ in terminal glycosylation capability will be evaluated in mice for their ability to induce humoral and cellular immune responses. Once optimal production method for VLPs is established, VLPs presenting all clades of HIV-1 Env and Gag antigens will be generated using baculovirus multigene expression system.